Digital output KL2531, KL2541 Digital output | 24/50 V DC, stepper motor terminals Bus Terminal 442 Stepper motors are often used in positioning drives. They allow, by the combination of single steps, a positioning process without feedback of the rotor positions. This “open control chain” mode of operation and the longevity of a stepper motor are particularly interesting for price-sensitive fields of application. However, safe positioning is only guaranteed within the performance limits. In contrast with a DC motor the control of a stepper motor is carried out by the different energisation of the individual motor windings following a defined pattern of pulses. The electromagnetic field of the stator is switched intermittently so that the shaft turns through the step angle α. The motor follows the impulse pattern of the control unit, until the coupled momentum exceeds its holding momentum or the impulse demand is too dynamic, which leads to standstill of the motor. With the KL2531 and KL2541 stepper motor terminals, which are suitable for highly dynamic movement, this problem in areas of higher speeds of rotation can be solved. The KL2531 and KL2541 stepper motor terminals are designed for direct connection of medium capacity stepper motors. A high frequency clocked PWM output stage regulates the currents through the motor coils. The stepper motor terminals are synchronised with the motor by parameterising. Unipolar as well as bipolar stepper motors can be driven. Additional inputs support functions like homing and final position monitoring. 64-fold micro stepping ensures particularly quiet and precise motor operation. Together with a stepper motor, the stepper motor terminals represent an inexpensive small servo axis. The KL2541 also includes an incremental encoder interface to read position data. Both KL2531 and KL2541 stepper motor terminals can be controlled like a servo drive by a speed interface from a Motion Control software such as TwinCAT for example. In applications with a less complex and less powerful CPU the control is also possible via a position interface (travel distance control). The stepper motor terminals move the motor themselves to a desired position. Ramp steepness and maximum speed can be entered as parameters. Irregular operation at certain speed ranges, particularly without coupled load, indicates that the stepper motor is being runat its resonance frequency. Under certain circumstances the motor may even stop. Resonances in the lower frequency range essentially result from the mechanical motor parameters. Apart from their impact on smooth running, such resonances can lead to significant loss of torque, or even loss of step of the motor, and are therefore particularly undesirable. Due to their sine/ cosine current profile, KL2531 and KL2541 stepper motor terminals are able to prevent this effect in almost all standard motors. The rotor is not moved from step to step, so it no longer jumps to the next position, but moves through 64 intermediate steps. So the rotor is carefully moved from one step to the next. The usual loss of torque at certain speeds is avoided and operation can be optimised for the particular application. This means that the lower speed range, where particularly high torque is available, can be fully utilised. The KL2531 stepper motor terminal is designed exclusively for 24 V supply voltage. The motor current can reach up to 1.5 A. The KL2541 covers a supply voltage range from 8 V DC to 50 V DC and also needs a 24 V supply from the power contacts. The motor current can be set from 1 to 5 A. The peak current may briefly significantly exceed the rated current and in this way makes the whole drive system very dynamic. In such dynamic applications, negative acceleration causes the feedback of energy, which leads to voltage peaks at the power supply unit. A KL9570 buffer capacitor terminal protects from the effects of overvoltage, in that it absorbs some of the energy. If the voltage exceeds the capacity of the terminal, it gets rid of the excess energy via an external resistance. AS10xx | Stepper motors see page AS20xx | Stepper motors see page 1 1 ​410 ​406 A1 A2 A1 A2 A1 A2 B1 B2 B1 B2 B1 B2 M M M Connection of a unipolar stepper motor Connection of a bipolar AS10xx stepper motor, serial Connection of a bipolar AS10xx stepper motor, parallel We reserve the right to make technical changes.